The hidden water pollutants27th January 2023
Imagine yourself standing on a cliff above what seems like a perfect beach surrounded by palm trees. You can’t wait to jump into the turquoise water. But when you reach the water, you notice the floating plastic bags, broken toys, and candy wrappers. Needless to say, that your wish to dive in is gone like the wind.
Unfortunately, this is the reality for many beaches from Hawaii to Bali, and this is just the trash you can see. Sometimes, pollution is very visible or you can even smell it, other times it may be more subtle. In agriculture, which plays a major role in water pollution, we have both – from “smelly” manure to chemical fertilizers which leak into the groundwater “unseen.”
Only 1 in 10 Americans is “pesticide-free”
The invention of synthetic nitrogen in the 20th century played a part in a boom in chemical-intensive, industrial farming practices. This was thought as a boon for humankind, but nitrate from agriculture has become the most common chemical contaminant in the world’s groundwater aquifers. Today, the world consumes 10 times more mineral fertilizer than it did in the 1960s. Pollution then occurs when fertilizers are applied more heavily than crops can absorb, or when they are washed or blown off the soil surface before they can be incorporated. In China, the world’s largest consumer of nitrogen fertilizer, up to half the nitrogen applied is lost by volatilization and another 5 to 10% by leaching.
Growth in crop production has also been achieved through the intensive use of pesticides. Farmers routinely use them to keep away unwanted weeds, insects, rodents, and fungi. Since becoming widespread in the past century, pesticides are routinely detected in 88% of US streams and rivers, and there’s only 1 in 10 Americans who don’t have pesticides in their body. Are you sure you’re that one person?
Where does animal poop go?
Cows, pigs, chickens, and turkeys do what all other animals do: poop. Their waste contains a high level of pathogens. Swine waste, for example, can contain more than 100 pathogens that cause human diseases. When animals are sick, they get antibiotics, but they often get them even if they are healthy. Animals digest them and dispose of them – again through poop.
All of that waste needs to go somewhere, and usually this is NOT to a wastewater treatment plant via a municipal sewer system. Instead, farmers spread it onto cropland to dispose of it. But, what they actually spread is a dangerous mix of animal manure, pathogens harmful for humans, leftovers of antibiotic treatments, and growth hormones. Far more is spread than what the plants need or the soil can absorb, and when it rains, this too seeps into groundwater.
Why is this a problem?
Contaminated groundwater, if consumed over a considerable period, may cause many human health problems, including hormone disruption, cancer, and reproductive abnormalities, including “blue baby syndrome,” a potentially fatal illness in infants. People can become sick also by ingesting water during swimming or kayaking, so it’s not only contaminated drinking water that is risky.
Water pollution also harms nature’s health. Pollutants directly harm soil microorganisms and larger soil-dwelling organisms, and so affect soil biodiversity and the services it provides. Nutrient overload causes excessive aquatic plant growth, known as “eutrophication”, leading to harmful algal blooms, which suppress other aquatic plants and animals. The results can be dramatic. Each summer, high levels of manure and fertilizer from the Mississippi River make their way into the Gulf of Mexico, causing a recurring “dead zone” thousands of miles wide. And even though this is a very visible consequence of water pollution, we don’t seem to see its long-term effects. We do, however, need to find long-term solutions.
On-farm practices that help prevent pollution
Given that less food production is not an option, we need to look at how to reorient current agricultural practices towards more sustainable models.
One of them is using green manure as the main source of nitrogen – as we do at LoginEKO. This helps us achieve different goals. One of them is to provide nitrogen for the next crop. The other is to prevent the leaching of nutrients into the deeper layers of the soil. Green manure also helps repair the structure and reduce soil compaction. The efficiency of sequestration (removing carbon from atmospheric CO2 and incorporating it into plant tissues through the process of photosynthesis) increases too. Last but not least, green manure helps us achieve broader environmental goals of reducing the emission of greenhouse gasses from the soil, preventing soil erosion, increasing biodiversity, and preventing crop contamination.
Phosphorus is an essential nutrient required for the growth and development of plants, and its status in soil can be improved using natural phosphorus fertilizers, which also directly prevents water pollution because there’s no leaching of toxic substances in the groundwater. Establishing protection zones along surface watercourses, within farms and in buffer zones around farms can also be effective in reducing pollution migration to water bodies.
These are only a few options to enable the transfer to sustainable production that will reduce water pollution on a global level. We urgently need to do this transfer because pollution of groundwater by agricultural chemicals and waste has become a major issue in almost all developed countries and, increasingly, in many developing countries. And while we can all live with not being able to swim around Bali or in the Gulf of Mexico, no one can live without safe drinking water. Though, being able to swim or kayak in christal clear waters is something we should strive to achieve too.